Loom let-off

ABSTRACT

A positive warp let-off mechanism for a loom having a continuously rotating cam adapted to intermittently rotate a ratchet wheel which through a transmission gear housing intermittently rotates a pair of driven rolls about which warp threads from the warp beam extend and by which said threads are drawn from said beam.

2,623 ,703 12/1952 Laycock United States Patent [72] lnventor Harold J.Coset-ta 2,649,864 8/1953 Mayer, Jr. et al. 139/97 l-lopedale, Mass.2,835,279 5/1958 Horowitz l39/97X [2.1 Appl. No. 830,239 3,086,5604/1963 Horak 139/110 [.221- Filed June 4, 1969 3,125,128 3/1964Pfarrwaller. 139/115 [45] Patented Jan. 5,1971 3,228,428 1/1966 Gray139/104 [73] Assignee North American Rockwell Corporation Pittsburgh,Pa. FOREIGN PATENTS acorporation of Delaw 265,511 10/1913 Germany 139/97Primary Examiner-James Kee Chi 54 00 LELOFF Attorney-John R. Bronaugh 5Claims, 5 Drawing Figs.

[52] 11.8. 139/100, 139/110 [51 Int. (I I D03d 49/06 [50] Fieldofsefllcll 139/110, ABSTRACT: A positive warp eboff mechanism for a |oom1 104 having a continuously rotating cam adapted to intermittentlyrotate a ratchet wheel which through a transmission gear [56] Referenceshousing intermittently rotates a pair of driven rolls about UNITEDSTATES PATENTS which warp threads from the warp beam extend and by which139/100X said threads are drawn from said beam.

P-ATENVTED JAN s l97l SHEET 1* [1F 3 INVENTOR HAROLD JCOSETTA ATTORNEYPATENTED JAN 5197! SHEET 2 OF 3 INVENTOR HARoLDJCosETTA ATTORNEYPATENTED m 5 m1 SHEET 3 OF 3 E IMM i w i INVEN TOR HAROLD J.CO5ETTAATTORNEY Qml LOOM LET-OFF The invention relates to an improved positivelet-off mechanism for looms of the type adapted to weave tightly wovenfabrics'such as duck or the like and in particular-pertains to amechanism that is easily and'accurately set up to obtain the desiredamount of crimp in-the fabric as it is formed.

, Known mechanisms of the prior art thatare adaptedto control the amountof crimp in woven fabric are considered quite utilizes a permanentgearing arrangement and by simply changing a cam controlled ratchetwheel which transmits the required motion to said gearing arrangement,or on some occasions the drive or driven sprocket, any desiredpercentage of crimp is quickly and accurately obtained.

SUMMARY OF THE INVENTION The let-off mechanism of the present inventionis actuated intermittently by a cam member fixed on and adapted torotate with the looms crankshaft. By means of a cam follower andcooperating linkages a ratchet wheel is intermittently rotated toprovideinput motion to a housed gearing arrange ment fixed .to theframework of a loom. The gearing output motion rotates a sprocket memberwhich in turn is in driving relation with sprocket members fixed on theends of a pair of rollers that are intermittently rotated for drawingthe warp yarns from the warp beam. A braking device is adapted tofunction in cooperation with thewarp beam and provides the required dragon said warp beam so-as to maintain a desired amount of tension on thewarp yarns as the latter are being withdrawn by the above-mentionedrollers.

It is an object of the invention to provide an improved warp let-offmechanism for a loom in which the percentage of crimp formed in thewoven fabric can be simply and accurately controlled and which can beincreased or decreased as desired with a minimum number of parts anddowntime of the loom.

BRIEF DESCRIPTION'OF'TI-IE DRAWING FIG. 1 is a viewin side elevation'ofa portion of a loom I showing the mechanism according to the inventionapplied thereto.

FIG. 2 is a plan view of the mechanism shown in FIG. 1.

FIG. 3 is a view in end elevation of the warp beam braking device asseen looking from the front of the loom.

FIG. 4 is a view in end elevation andpartially in section of the gearingarrangement for transmitting motion to the-rollers which draw the warpyarn from the warp beam, and'FIG. 5 is an end view partially in sectionof the gearing; arrangement.

shown in FIG. 4. i I

DESCRIPTION OFTHEPREFERRED EMBODIMENT Referring to the drawings whereinonly as much of conventional loom structure is depicted as is necessaryto a complete understanding of the invention, there is shown-inxFlG. l aportion of the left-hand loomside having a combined driven and drag rollsupport stand- 11 fixedly attached. thereto by means of bolts 12 and 13.

A crankshaft 14 (FIG. 1) extends between the loomsides in the usualmanner and the left-hand end thereof which extends outwardly beyond theloomside 10 has a'cam member 15 fixed thereon for rotation with saidcrankshaft.

The support stand 11 hasa gear box 16 (FIGS. I, 4 and 5) attached by anysuitable means (not shown) to the side thereof which includes a lowermotion input shaft 17 and an upper motion output shaft I8. As shown inFIGS. 4 and 5, the gearing arrangement within the gear box 16 includes abevel gear 19 that is fixed on and adapted to rotate with shaft 17.Bevel gear 19 is in driving relationwith a second bevel gear 20 thelatter of which is assembled on the lower end of a drive shaft 2]. Thisdrive shaft is supported vertically within the gear box 16 and has fixedthereon-adjacent its upper end a worm gear 22. Worm gear 22 is indriving relation with a worm wheel 23, the latter of which assembles onshaft I8 and which is rotated according to the dictates of the motioninput shaft 17.

Shaft 17 extends outwardly from the gearbox 16 as shown at 24 in FIG. 4and immediately adjacent to said box has pivotably assembled thereon ata point intermediate its ends a pawl support arm 25. (FIG. I). Thissupport arm carries at'its upper end a pivotable pawl member 26 that isengageable with teeth 27 of a ratchet wheel 28. Ratchet wheel 28assembles on shaft 17 and is adapted to intermittently rotate the latterin a manner now to be described.

The pawl support arm adjacent its lower end has one end of a drive rod29 pivotably attached thereto as at 30 and the opposite end thereof ispivotably and adjus'tably attached'by means of a bolt 31 to a camfollower support arm 32 (FIG. 1). The cam' follower support arm ispivotably supported by means of a bolt 33 on a bracket 34 which isattached to the loomside 10 by bolts 35. This supportarm includes anarcu ated slot 36 through which bolt 31 extends and permits adjustmentof the forward end of drive rod 29 within the limits of said slot. Anintegrally formed and laterally extending lug 37 is disposed at theforward upper side of the support arm'and provides a means for assemblyof a rotatable cam follower 38 thereto.

The cam follower 38 is adapted to track I on the outer periphery of therotating cam member 15 and is held in contacttherewith by means of acoil spring 39. One end of this coil spring 39 attaches to the lower endof the pawl support arm 25 as at 40 and the opposite end is attached toa spring bracket 41 the latter of which is fastened tothe loomside 10 byany suitable means.

It can be easily seen that drive rod 29 is caused to reciprocate whenthe support arm is pivoted to and fro by means of the motion created bycam member 15 and the cam follower 38. This reciprocating movementoscillates the pawl support arm 25 and the pawl member 26 carried on theupper end thereof engages each tooth of the ratchet wheel 28Suecessively and intermittently rotates the latter in the direction ofthe indicating arrow 42 as shown inFIG. 1.

The intermittent rotary movement of the ratchet wheel is transmittedthrough the gearing arrangement to a drive sprocket 43 which is fixedonthat portion'of the motion butput shaft 18 that extends outwardly fromthe gear box 16. I As shown in FIGS. 1 and 2, the support 's'tan'dll isprovided with an integrally formed and rearwardly extending arm 44 whichis adapted to rotatably support one end of a pair of spaced paralleldriven rolls 45 and 46 by means of their gudgeons 47 and48beingjournaled in integrally formed housings 49 and 50 respectively.It should be understood that the opposite ends of these driven rollsareprovided with similar gudgeons and are rotatably supported in a likemanner by a support stand that is attached to the right-hand loomsiden'ot shown.

Gudgeons 47 and 48 extend outwardly beyond their respective housings 49and 50' and have fixed thereon'aligned sprocket members 51 and 52 thatare interconnected by a sprocket chain 53.

Gudgeon 48 extends outwardly for a greater distance than gudgeon 47 andhas a driven sprocket 54 fixed thereon immediately adjacent to sprocketmember. 52. A sprocket chain 55 interconnects the driven sprocket 54-"with the drive sprocket 43 and causes' the intermittent rotary movementof the latter to-be transmitted to the driven rolls 45 and 46.

In FIG. 1 the warp yarn is depicted by numeral 56 and the yarn beamabout which it is wrapped by numeral 57. Like the driven rolls 45 and 46the yarn beam 57 includes gudgeons for its support and the left handonly being shown in FIG. I is identified by numeral 58. A yarn beambearing 59 supports the yarn beam for rotary movement and is assembledto the lower rearward end of the loomside by means of bolts 59 and nuts60.

A pair of drag roll brackets 61 and 62 (FIGS. 1 and 2) are attached tothe inner side of the support stand 11 by means of bolts 63 and 64,respectively. Bracket 61 supports the end of a drag roll 65 and bracket62 the end of a drag roll 66. These drag rolls are horizontally disposedand positioned in spaced and parallel relation. Drag roll 65 issupported intermediate the driven rolls 45 and 46 and drag roll 66forward of the driven roll 46. Additionally, the drag roll brackets 61and 62 are vertically adjustable allowing the drag rolls 65 and 66 to beraised or lowered whereby the amount of wrap of the warp yarn 56 aboutthe driven rolls can be increased or decreased as best suited for aparticular weaving condition.

The support stand 11 further includes an integrally formed and upwardlydirected bracket element 67 (FIGS. 1 and 2) the inner surface of whichprovides a means for supporting the ends of an additional pair of dragrolls 68 and 69 having mounting plates 70 and 71, respectively, fixedlyattached to the ends thereof. These additional drag rolls are disposedgenerally one above the other and the lower one 68 being approximatelytwice the diameter of the upper roll 69 is fixed to the bracket element67 by means of bolts 72.

The upper drag roll 69 is radially adjustable relative to its companionroll 68 so as to permit an increase or decrease in the area of contactby the warp yarn on the outer surface of said roll 68. This upper dragroll is attached to bracket element 69 by means of bolts 73 and by meansof a pair of arcuated slots 74 and 75 in the mounting plate 70 throughwhich said bolts pass, the roll 69 can be moved to any desired positionwithin the limits of said slots.

The warp yarn 56 as shown in FIG. 1 is drawn from the warp beam 57 bythe driven rolls 45 and 46 which may have any suitable type of covering,such as rubber, to increase traction and prevent slippage thereon ofsaid warp yarns. The warp beam is rotatable, and to maintain tension onthe warp yarn 56 as it is drawn from the beam, it is necessary that abraking device be provided to produce a drag on the beam. The brakingdevice may be of any desired type and the one shown in FIGS. 1 and 2 isof the caliper type such as furnished by H. H. Products Division ofKelsey Hayes Co. of 860! N. 43rd Street, Milwaukee, Wisconsin.

A disc 76 is fixed on gudgeon 58 intermediate the yarn beam 57 and theyarn beam bearing 59. The braking device is identified generally inFIGS. 1 and 2 by numeral 77 and includes opposed spring biased plates 78and 79 with the opposed faces thereof having arcuated brake elements orsocalled pucks 80 and 81 fixed thereon. A portion of the disc passesbetween the pucks as it is caused to rotate with the yarn beam and saidpucks are caused to bear against the sides thereof thereby producing adrag on the yarn beam. The means for applying and releasing this brakingforce includes a cam-type lever 82 having an adjustable spring tensionedactuating rod 83 pivotably connected at one end thereto. The oppositeend of this actuating rod is mechanically linked to a double armed lever84 that is rockable to apply or release the braking force by means of apivotable brake lever 85.

In operation, the warp yarn is drawn from the warp beam intermittentlyby the driven rolls 45 and 46 which receive their intennittent rotarymotion through their driving connections with the gear box 16. The cammember 15 which rotates continuously on the looms cranksahft and whichprovides the intermittent motion to the gear box 16 can be timed and setto actuate the elements cooperating therewith, at any degree of rotationof said crankshaft. This feature is considered advantageous because,relative to the takeup and beat up of the loom, the warp yarn can belet-off at the most feasible time for anyqparticular weaving condition.

e warp yarn 15 held under the desired amount of tension as it is drawnfrom the warp beam by means of the braking device adapted to function incooperation therewith. The warp yarn passes over the top of the drivenrolls 45 and 46 and beneath the drag rolls 65 and 66 disposedimmediately adjacent to said driven rolls.

After leaving drag roll 66 as shown in FIG. 1 the warp yarn passes overthe top and forward portion of drag roll 69 and thence downwardly aroundthe back and lower portion of drag roll 68. The combination of dragrolls 68 and 69 is instrumem tal in preventing a loss in yam tensionin'the driving area during the time of filling yarn beat up. Afterleaving drag roll 68, the warp yarn is advanced through the usual stopmotion device and harness frames not shown.

I claim:

1. A positive warp let-off mechanism for a loom having a rotatablydriven shaft member and a warp beam upon which a multiplicity of warpyarns are wound, the improvement which comprises:

a. a pair of spaced and horizontally disposed driven rolls for drawingthe warp yarns from said warp beam;

b. a first pair of drag rolls disposed adjacent said driven rolls forincreasing the area of surface contact of said warp yarns thereon;

c. a second pair of drag rolls spaced from said driven rolls formaintaining tension on said warp yarns;

d. a drive sprocket interconnected by chain members to said drivenrolls;

e. cam actuated drive means for intermittently rotating said drivesprocket and driven rolls to advance said warp yarns in timed relationto the looms fabric takeup mechanism; and

f. a braking means functioning in cooperation with said warp beam formaintaining desired tension on said warp yarns as they are drawn fromthe warp beam.

2. The warp let-off mechanism according to claim 1 wherein said camactuated drive means includes a gear box for rotating said drivesprocket and a ratchet wheel for transmitting intermittent rotary motionthrough said gear box to said drive sprocket.

3. The warp let-off mechanism according to claim 2 wherein said drivemeans further includes a cam fixed on and for rotation with saidrotatably driven shaft member and a cam follower with interconnectinglinkages for transmitting the dictates of said cam to said ratchetwheel.

'4. The warp let-off mechanism according to claim 3 wherein saidinterconnecting linkages comprise:

a. a pivotable pawl engageable with the outer periphery of said ratchetwheel;

b. a pawl support arm oscillatably carried by said gear box in axialalignment with said ratchet wheel; and

c. a drive rod interconnecting said support arm with a lever carryingsaid cam follower for transmitting intermittent indications from saidcam to said ratchet wheel.

5. The warp let-off mechanism according to claim 4 wherein said supportarm includes a biasing means for maintaining said cam follower incontact with the outer periphery of said cam.

1. A positive warp let-off mechanism for a loom having a rotatablydriven shaft member and a warp beam upon which a multiplicity of warpyarns are wound, the improvement which comprises: a. a pair of spacedand horizontally disposed driven rolls for drawing the warp yarns fromsaid warp beam; b. a first pair of drag rolls disposed adjacent saiddriven rolls for increasing the area of surface contact of said warpyarns thereon; c. a second pair of drag rolls spaced from said drivenrolls for maintaining tension on said warp yarns; d. a drive sprocketinterconnected by chain members to said driven rolls; e. cam actuateddrive means for intermittently rotating said drive sprocket and drivenrolls to advance said warp yarns in timed relation to the looms fabrictakeup mechanism; and f. a braking means functioning in cooperation withsaid warp beam for maintaining desired tension on said warp yarns asthey are drawn from the warp beam.
 2. The warp let-off mechanismaccording to claim 1 wherein said cam actuated drive means includes agear box for rotating said drive sprocket and a ratchet wheel fortransmitting intermittent rotary motion through said gear box to saiddrive sprocket.
 3. The warp let-off mechanism according to claim 2wherein said drive means further includes a cam fixed on and forrotation with said rotatably driven shaft member and a cam follower withinterconnecting linkages for transmitting the dictates of said cam tosaid ratchet wheel.
 4. The warp let-off mechanism according to claim 3wherein said interconnecting linkages comprise: a. a pivotable pawlengageable with the outer periphery of said ratchet wheel; b. a pawlsupport arm oscillatably carried by said gear box in axial alignmentwith said ratchet wheel; and c. a drive rod interconnecting said supportarm with a lever carrying said cam follower for transmittingintermittent indications from said cam to said ratchet wheel.
 5. Thewarp let-off mechanism according to claim 4 wherein said support armincludes a biaSing means for maintaining said cam follower in contactwith the outer periphery of said cam.